1. Field of the Invention
The present invention relates to a potential generator circuit of a semiconductor memory. In particular, the present invention relates to a sense amplifier reference potential generator circuit of a memory using a ferroelectric capacitor.
2. Description of the Related Art
Conventionally, a sense amplifier reference potential used for a semiconductor memory, for example, ferroelectric memory, has kept a constant value, which does not depend on temperature. Thus, the study of giving a desired temperature dependency to the potential has not been made.
A BGR circuit has been conventionally used only for generating a reference potential having no temperature dependency. As shown in FIG. 1 and FIG. 2, it has been known that the area or resistance ratio of a diode is varied, thereby obtaining an output potential having temperature dependency. However, it is difficult to independently control the temperature dependency and its absolute value. There is the following problem; more specifically, if high temperature dependency is set, the absolute value also becomes large, as seen from FIG. 3.
For example, the following technique is desired in the field of ferroelectric memory. Temperature dependency is given to a sense amplifier reference potential in accordance with ferroelectric thin film characteristics, and the temperature dependency and the absolute value are independently controlled in their setting.